Robostix simple servo

From GumstixDocsWiki

This page describes one way to control an R/C servo from the Robostix.

The servo on the left (a simple standard servo) draws 170ma when operating with no load. The servo on the right draws 350ma when operating with no load. When stalled, these servos can draw an amp or two each, well in excess of the rated currect capacity of the standard wall wart that comes with the gumstix.

With the jumper cut, the power for the six PWM connectors will be provided from the MOTOR connector, so these six positions are the only really safe place to plug a servo into.

Potentiometer Board

Also visible in the photo, is quick little board I whipped up which has two 10K potentiometers on it.

The TinyCAD file used to create this is available here.

Running the sample

There are two versions of the sample program, one called Simple-Servo and one called Simple-Servo-2

Simple-Servo uses some C macros to control the servos, while Simple-Servo-2 uses some functions from Servo.c

Varying the potentiometer will change the servo position. Be careful near the extremes since servo behave differently when you get there.